Undesirable nitrosamines are often found in herbicidal and other compositions or formulations which contain constituents having (a) nitrosatable nitrogen functional groups, such as secondary or tertiary amines, in addition to (b) materials with potential nitrosating activity, such as 2,4-dinitro-6-sec-butylphenol (dinoseb) contaminated with a nitrosating agent or agents, such as HONO or precursors thereof.
For example, contaminating amounts of N-nitrosodiethanolamine (NDELA) can be found in formulations made with alkanolamines, e.g., mixtures of alkanolamines containing triethanolamine and diethanolamine, and technical grades of 2,4-dinitro-6-sec-butylphenol. Such undesirable product is formed by the combination of diethanolamine and/or triethanolamine in the alkanolamine mixture and nitrosating agents or precursors thereof present as impurities in the 2,4-dinitro-6-sec-butylphenol. Typically, there are no significant nitrosamine levels in the technical grade 2,4-dinitro-6-sec-butylphenol or in any of the formulating agents prior to the time the constituents are mixed together.
Since nitrosamines have been reported to cause tumors in rats, compositions or formulations having potential for nitrosamine formation may present the possibility of adverse effects on people involved in the handling and use of such materials. Thus, any means to minimize the formation of nitrosamines in such compositions or formulations is desirable.